Physiological detection system with adjustable signal source and operating method thereof

ABSTRACT

A physiological detection system including a light source module, a photo sensor and a processor is provided. The light source module is configured to provide light to illuminate a skin region. The photo sensor is configured to detect emergent light passing the skin region with at least one signal source parameter and output an image signal. The processor is configured to calculate a confident level according to the image signal to accordingly adjust the at least one signal source parameter.

BACKGROUND

1. Field of the Disclosure

This disclosure generally relates to an optical physiological detectionsystem and, more particularly, to a physiological detection system withadjustable signal source and an operating method thereof.

2. Description of the Related Art

Conventional pulse oximeters utilize a noninvasive method to monitor theblood oxygenation and the heart rate of a user. The conventional pulseoximeters generally emit a red light beam (wavelength of about 660 nm)and an infrared light beam (wavelength of about 910 nm) to penetrate apart of the human body and detect an intensity variation of penetratinglight based on that the oxyhemoglobin and the deoxyhemoglobin havedifferent absorptivities in particular spectrum. After the intensityvariation of the penetrating light, e.g. photoplethysmography signal orso called PPG signal, of the two wavelengths is detected, the bloodoxygenation can then be calculated according to the following equation:Oxygen saturation=100%×[HbO2]/([HbO2]+[Hb])

wherein [HbO2] is oxyhemoglobin concentration; and [Hb] isdeoxyhemoglobin concentration.

Generally, the intensity variation of the penetrating light of the twowavelengths detected by a pulse oximeter becomes strong and weak withthe heartbeat. This is because blood vessels will expand and contractwith the heartbeat such that the blood volume that the light beams passthrough will change to accordingly change the ratio of light energybeing absorbed. Accordingly, it is able to calculate a physiologicalcharacteristic of the user according to the detected PPG signal(s).

However, when an optical physiological detection device is applied to aportable device or a wearable device, a detection surface thereof canhave a relative movement with respect to a skin surface or the detectionsurface is not tightly attached to the skin surface such that the signalquality of detected signals is reduced to degrade the detectionaccuracy.

SUMMARY

Accordingly, the present disclosure provides a physiological detectionsystem with high accuracy and an operating method thereof so as toincrease the applicable range thereof.

The present disclosure provides a physiological detection system withadjustable signal source and an operating method thereof that improvethe signal quality and detection accuracy by adjusting at least onesignal source parameter.

The present disclosure provides a physiological detection systemincluding a physiological detection module. The physiological detectionmodule includes a light source module, a photo sensor and a firstprocessor. The light source module is configured to provide light toilluminate a skin region. The photo sensor is configured to detectemergent light passing the skin region with at least one signal sourceparameter and output an image signal. The first processor is configuredto calculate a first confident level according to the image signal andupdate the at least one signal source parameter according to the firstconfident level.

The present disclosure further provides an operating method of aphysiological detection system. The physiological detection systemincludes a physiological detection module. The operating method includesthe steps of: detecting, by the physiological detection module, emergentlight from a skin region with at least one signal source parameter togenerate an image signal; calculating, by the physiological detectionmodule, a confident level according to the image signal; comparing, bythe physiological detection module, the confident level with at leastone threshold; and updating, by the physiological detection module, theat least one signal source parameter according to a comparison result ofcomparing the confident level and the at least one threshold.

The present disclosure further provides an operating method of aphysiological detection system. The physiological detection systemincludes a physiological detection module and an application modulecoupled to each other. The operating method includes the steps of:detecting, by the physiological detection module, emergent light from askin region with at least one signal source parameter to generate animage signal; calculating, by the physiological detection module, afirst confident level according to the image signal; outputting, by thephysiological detection module, an intensity variation signal accordingto a plurality of image signals; calculating, by the application module,a second confident level according to the intensity variation signal;and updating the at least one signal source parameter according to thefirst confident level and the second confident level.

In the physiological detection system and operating method according tothe present disclosure, the confident level includes, for example, atleast one of an average brightness value, uniformity, aphotoplethysmography (PPG) signal amplitude, a signal to noise ratio(SNR) and other image quality parameters. The signal source parameterincludes, for example, at least one of an exposure time, a gain value, awindow of interest (WOI), a light emitting intensity, a focus length anda light receiving phase.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, advantages, and novel features of the present disclosurewill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

FIG. 1 is a schematic block diagram of a physiological detection systemaccording to one embodiment of the present disclosure.

FIG. 2 is a schematic diagram of a window of interest of a pixel arrayaccording to one embodiment of the present disclosure.

FIG. 3 is a schematic diagram of an intensity variation signal generatedby a physiological detection system according to one embodiment of thepresent disclosure.

FIG. 4 is a schematic diagram of different light receiving phasesaccording to one embodiment of the present disclosure.

FIG. 5 is a schematic diagram of frequency domain data generated by aphysiological detection system according to one embodiment of thepresent disclosure.

FIG. 6 is a flow chart of an operating method of a physiologicaldetection system according to a first embodiment of the presentdisclosure.

FIG. 7 is a flow chart of an operating method of a physiologicaldetection system according to a second embodiment of the presentdisclosure.

FIG. 8 is a flow chart of an operating method of a physiologicaldetection system according to a third embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF THE EMBODIMENT

It should be noted that, wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

Referring to FIG. 1, it is a schematic block diagram of a physiologicaldetection system 100 according to one embodiment of the presentdisclosure. The physiological detection system 100 includes aphysiological detection module 11 and an application module 13 coupledto each other. The physiological detection module 11 is configured toemit light toward a skin region SR to penetrate a part of body tissuesand detect emergent light passing the skin region SR to generate animage signal IF, wherein the skin region SR is at different parts of thehuman body according to different applications, e.g. the finger, ankle,wrist, ear or forehead, without particular limitations. The applicationmodule 13 is one of a portable electronic device, a wearable electronicdevice, a home appliance, a vehicle device and a medical device. Theapplication module 13 communicates with the physiological detectionmodule 11, e.g. sending data, in a wired or wireless manner, andpresents the detected physiological characteristics.

It should be mentioned that although FIG. 1 shows that the physiologicaldetection module 11 and the application module 13 are separated, thepresent disclosure is not limited thereto. In other embodiments, thephysiological detection module 11 is integrated in the applicationmodule 13.

The physiological detection module 11 includes a light source module111, a photo sensor 113, a first processor 115, a storage unit 117 and atransmission interface 119.

The light source module 111 includes, for example, a coherent lightsource, a partially coherent light source or a non-coherent light sourcewithout particular limitations, e.g. including a light emitting diode ora laser diode. The light source module 111 is configured to providelight to illuminate a skin region SR, and after entering skin tissues ofthe skin region SR, the light propagates a distance and then ejects fromthe skin region SR, wherein the light intensity of emergent lightfluctuates with time due to a part of light energy being absorbed byblood. In some embodiments, an emission wavelength of the light sourcemodule 111 is that used in conventional pulse oximeters. In otherembodiments, an emission wavelength of the light source module 111 isbetween 300 nm and 940 nm. It should be mentioned that although FIG. 1shows a single light source, it is only intended to illustrate but notto limit the present disclosure. In some embodiments, when thephysiological detection system 100 is used to detect the bloodoxygenation, the light source module 111 includes two light sourcesrespectively configured to emit red light and infrared light. In otherembodiments, when the physiological detection system 100 has thecorrection function, the light source module 111 includes three lightsources respectively configured to emit green light, red light andinfrared light, wherein a PPG signal associated with the green light isconfigured to determine a filter parameter which is used to filter PPGsignals associated with the red light and the infrared light. In otherembodiments, in order to change the light emitting intensity of thelight source module 111, the light source module 111 includes aplurality of light sources emitting light of a same wavelength orincludes a light source with adjustable drive current.

The photo sensor 113 is configured to detect emergent light passing theskin region SR with at least one signal source parameter, and output animage signal IF at every sample period. Accordingly, image signals IFcorresponding to a plurality of sample periods form an intensityvariation signal. In some embodiments, the photo sensor 113 is a photodiode, and the intensity variation signal outputted therefrom isconfigured as the PPG signal. In some embodiments, the photo sensor 113is an image sensor which includes a pixel array having a plurality ofpixels. Every pixel of the pixel array outputs an image signal IF in animage frame and the first processor 115 is configured to calculate a sumof image signals of a plurality of pixels of the image frame, whereinthe variation of the sum of image signals with time is configured as aPPG signal. In some embodiments, the variation of image signals IF withtime outputted by each of the pixels of the pixel array is configured asa PPG signal, i.e. the photo sensor 113 outputting a plurality ofintensity variation signals. In addition, in some embodiments, when thephoto sensor 113 is an image sensor, it is preferably an active imagesensor, e.g. a CMOS image sensor, such that a window of interest (WOI)as shown in FIG. 2 is selectable according to the signal distributionactually detected by the pixel array. It is appreciated that a positionof the window of interest (WOI) is not limited to that shown in FIG. 2.

The first processor 115 is, for example, a digital signal processor(DSP) and is configured to receive image signals IF outputted from thephoto sensor 113 for post-processing, e.g. generating an intensityvariation signal according to a plurality of image signals IF to beconfigured as the PPG signal. For example, the first processor 115receives the image signal IF from the photo sensor 113 and successivelyretrieves a plurality of image signals IF within a time interval, e.g.5-10 seconds, to be configured as the PPG signal. For example, FIG. 3shows the intensity variation signal within a time interval of 6 secondsconfigured as the PPG signal, but the present disclosure is not limitedthereto. FIG. 3 is a schematic diagram of an intensity variation signal(or PPG signal) generated by the physiological detection systemaccording to one embodiment of the present disclosure. As the photosensor 113 sequentially outputs image signals IF at a sample frequency(or frame rate), the time intervals are partially overlapped or notoverlapped with each other in time. For example, the first processor 115takes the intensity variation signal within 0-6 seconds as a PPG signal,and then takes the intensity variation signal within 1-7 seconds as anext PPG signal or takes the intensity variation signal within 7-13seconds as a next PPG signal and so forth.

When the photo sensor 113 is a photodiode, the first processor 115directly retrieves the intensity variation signal outputted by the photosensor 113 as the PPG signal, wherein the first processor 115 does notprocess the intensity variation signal. In some embodiments, the firstprocessor 115 performs only the pre-processing, such as the filtering oramplifying, on the intensity variation signal to generate the PPGsignal.

When the photo sensor 113 is an image sensor, the first processor 115calculates a sum of image signals (e.g. implemented by software) of atleast a part of pixels (e.g. within the WOI) of every image frameoutputted by the pixel array, and successively calculates the sum ofimage signals for a time interval. e.g. 5-10 seconds, to be configuredas the PPG signal, as shown in FIG. 3. In other embodiments, when thephoto sensor 113 is an image sensor and the image sensor itself has thefunction of calculating the sum of image signals (e.g. implemented byhardware), the first processor 115 retrieves the sum of image signalsfor a time interval, e.g. 5-10 seconds, to be configured as the PPGsignal; and in this embodiment, the first processor 115 does not processthe sum of image signals or performs only the pre-processing on the sumof image signals such as the filtering or amplifying. In other words,the PPG signal herein is the time variation of image signals outputtedby a photodiode, or the time variation of image signals of a singlepixel or the sum of image signals of a plurality of pixels.

In this embodiment, the first processor 115 is configured to calculate afirst confident level according to the image signal IF and update atleast one signal source parameter AP according to the first confidentlevel.

In one embodiment, the first confident level includes at least one of anaverage brightness value and uniformity. During operation, a detectionsurface of the physiological detection module 11 is preferably tightlyattached to the skin region SR to prevent ambient light from beingreceived by the photo sensor 113. Accordingly, an average brightnessvalue of the image signal IF outputted by the photo sensor 113 ispreferably lower than a first brightness threshold to make sure that thephoto sensor 113 does not receive the ambient light. In addition, inorder to be able to use the image signal IF outputted by the photosensor 113 to calculate physiological characteristics, an averagebrightness value of the image signal IF outputted by the photo sensor113 is preferably higher than a second brightness threshold to make surethat the photo sensor 113 receives enough emergent light. In anotherembodiment, when the photo sensor 113 includes a pixel array, uniformityof the image frame (i.e. the image signal IF) outputted by the photosensor 113 is preferably higher than a predetermined threshold to makesure that the image quality of the image frame is good enough forcalculating physiological characteristics. When the first confidentlevel does not satisfy a predetermined condition (e.g. the abovethresholds), the first processor 115 updates the at least one signalsource parameter AP, wherein the predetermined condition is satisfiedwhen, for example, the first confident level is within a thresholdrange, larger than a threshold or smaller than a threshold depending onthe first confident level being used.

In one embodiment, the at least one signal source parameter AP isselected from a group consisting of an exposure time, a gain value, awindow of interest (WOI), a focus length and a light receiving phase.The exposure time is referred to an exposure time of each sample periodof the photo sensor 113. The gain value is referred to a gain (e.g.analog or digital gain) for amplifying detected signals of the photosensor 113. The window of interest is used to select a pixel area, e.g.shown in FIG. 2, having a higher confident level or having brightnesswithin a predetermined range. The focus length is adjusted, for example,by a motor (e.g. a voice coil motor). The receiving phase is used tochange a phase of emergent light received from the skin region SR. Forexample, referring to FIG. 4, it shows that two pixels P1 and P2respectively receive emergent light at different angles (or phases), andthe region filled with oblique lines is referred to the opaque metallayer, e.g. forming different light tunnels by a plurality of metallayers (e.g. M1-M10) in the CMOS process such that different pixelsreceive emergent light at different angles (or phases). It should bementioned that although FIG. 4 shows only two pixels, it is onlyintended to illustrate but not to limit the present disclosure. Thenumber of pixels receiving emergent light at a same phase is determinedaccording to different applications without particular limitations. Itis appreciated that when the photo sensor 113 includes a singlephotodiode, the at least one signal source parameter AP does not includethe window of interest (WOI) and the light receiving phase.

In other embodiments, the at least one signal source parameter AP isfurther configured to control a light emitting intensity of the lightsource module 111, e.g. adjusting the light emitting intensity bychanging the drive current, the number of light sources being activatedor a light source distance.

The storage unit 117 is, for example, a register or a memory, e.g. RAM.The storage unit 117 is coupled to the first processor 115 andconfigured to temporarily store the image signal IF, the intensityvariation signal (or PPG signal), the first confident level CL, the atleast one signal source parameter AP and algorithms.

The transmission interface 119 is configured to communicate with anexternal device, e.g. sending the image signal IF, the intensityvariation signal (or PPG signal), the first confident level CL and/orthe signal source parameter AP to the external device. The transmissioninterface 119 is, for example, a wired transmission interface (e.g. I2C,SPI, USB or the like) or a wireless transmission interface (e.g.Bluetooth interface).

The application module 13 is coupled to the physiological detectionmodule 11 to be configured as the external device of the physiologicaldetection module 11. The application module 13 is configured to receivethe image signal IF, the intensity variation signal (or PPG signal), thefirst confident level CL and/or the signal source parameter AP toperform corresponding processes and controls, wherein the firstconfident level CL is served as a reference for further adjusting thesignal source parameter AP. The application module 13 informs thephysiological detection module 11 to output data and sends the updatedsignal source parameter AP back to the physiological detection module11. The application module 13 includes a sensor drive unit 131, a secondprocessor 133 and a peripheral drive unit 135.

The sensor drive unit 131 is configured to drive the physiologicaldetection module 11 and setup the wired or wireless communication to thetransmission interface 119 so as to receive the image signal IF, theintensity variation signal (or PPG signal), the first confident level CLand/or the signal source parameter AP from the transmission interface119 and send the updated signal source parameter AP back to thetransmission interface 119. In other words, the sensor drive unit 131also includes a transmission interface. In the present disclosure, theat least one signal source parameter AP is updated according to thefirst confident level and/or a second confident level (calculated by theapplication module 13). The method of transmitting data between twodevices in a wired or wireless manner is known to the art and thusdetails thereof are not described herein.

The second processor 133 is, for example, a microcontroller (MCU) or acentral processing unit (CPU) and is configured to calculate a secondconfident level according to the intensity variation signal (or PPGsignal). The second processor 133 is further configured to update the atleast one signal source parameter AP when necessary. In one embodiment,the second confident level includes, for example, at least one of a PPGsignal amplitude and a signal to noise ratio.

For example, after receiving the PPG signal (e.g. shown in FIG. 3), thesecond processor 133 compares the amplitude of the PPG signal with atleast one threshold. When the PPG signal amplitude is within apredetermined threshold range, it means that the emergent light detectedby the photo sensor 113 is suitable to calculate physiologicalcharacteristics such that the at least one signal source parameter AP isnot adjusted. When the PPG signal amplitude is not within thepredetermined threshold range, the at least one signal source parameterAP is adjusted.

For example, the second processor 133 converts the intensity variationsignal to the frequency domain at first as shown in FIG. 5. FIG. 5 is aschematic diagram of frequency domain data generated by thephysiological detection system according to one embodiment of thepresent disclosure. The second processor 133 calculates a ratio betweena target spectrum (e.g. with maximum spectrum energy or a predeterminedspectrum) and a sum of other spectrum energy to be configured as asignal to noise ratio (SNR). Then, the second processor 133 compares theSNR with at least one threshold. For example, when the SNR is largerthan a predetermined threshold, the at least one signal source parameterAP is not adjusted; whereas when the SNR is smaller than thepredetermined threshold, the at least one signal source parameter AP isadjusted.

The second processor 133 is further configured to calculatephysiological characteristics according to the intensity variationsignal (or PPG signal), wherein the physiological characteristicsinclude, for example, a blood oxygenation, a heart rate, a respirationrate, a second derivative of photoplethysmogram (SDPPG) or the like. Themethod of calculating the physiological characteristics according to thePPG signal is known to the art and thus details thereof are notdescribed herein.

The peripheral drive unit 135 is configured to drive a peripheral deviceto present the physiological characteristics, e.g. driving a display toshow the physiological characteristics or give a warning, or driving aspeaker to play the physiological characteristics or give a warning,wherein the method of driving a peripheral device is known to the artand thus details thereof are not described herein.

Referring to FIG. 6, it is a flow chart of an operating method of aphysiological detection system according to a first embodiment of thepresent disclosure, which includes the steps of: capturing an image(Step S61); calculating a confident level (Step S62); comparing theconfident level with at least one threshold (Step S63); updating atleast one signal source parameter and adjusting signal source (StepS64); and storing information (Step S65). The operating method of thisembodiment is applicable to the physiological detection system 100 ofFIG. 1.

Referring to FIGS. 1-4 and 6 together, details of the first embodimentis illustrated hereinafter.

Step S61: The physiological detection module 11 detects emergent lightfrom a skin region SR with at least one signal source parameter AP togenerate an image signal IF. For example, the light source module 111 ofthe physiological detection module 11 illuminates at the skin region SRand the photo sensor 113 of the physiological detection module 11detects the emergent light from the skin region SR to generate an imagesignal IF in every sample period.

Step S62: The physiological detection module 11 calculates a confidentlevel CL according to the image signal IF. For example, the firstprocessor 115 of the physiological detection module 11 calculates atleast one of an average brightness value and uniformity to be configuredas the confident level CL. When the photo sensor 113 includes a pixelarray, the first processor 115 calculates an average brightness value oruniformity of the whole image frame outputted by the pixel array, orcalculates an average brightness value or uniformity of a part of (e.g.the window of interest in FIG. 2) image frame outputted by the pixelarray.

Step S63: The first processor 115 of the physiological detection module11 compares the confident level CL with at least one threshold, whereinthe at least one threshold is previously stored in the storage unit 117of the physiological detection module 11. A number of the at least onethreshold is determined according to different applications. Forexample, the first processor 115 compares the confident level CL with aplurality of thresholds to confirm whether the confident level CL iswithin a predetermined threshold range, wherein the predeterminedthreshold range indicates that the image signal IF is a valid imagesignal and suitable to perform the following calculation. For example,the first processor 115 compares the confident level CL with a singlethreshold to confirm whether the confident level CL is larger than (orequal to) or smaller than (or equal to) the single threshold.

Step S64: When the confident level CL is not within the predeterminedthreshold range, the at least one signal source parameter AP is updatedaccording to a comparison result of comparing the confident level CL andthe at least one threshold, and the signal source is adjusted. Forexample, when the at least one signal source parameter AP includes anexposure time, the first processor 115 adjusts the exposure time of thephoto sensor 113. For example, when the at least one signal sourceparameter AP includes a gain value, the first processor 115 adjusts thegain of the photo sensor 113. For example, when the at least one signalsource parameter AP includes a window of interest (as shown in FIG. 2),the first processor 115 adjusts the size and position of the window ofinterest. For example, when the at least one signal source parameter APincludes a focus length, the first processor 115 controls a motor toadjust the setting of focus length of the photo sensor 113. For example,when the at least one signal source parameter AP includes a lightreceiving phase, the first processor 115 changes the pixel of the photosensor 113 that outputs the image signal IF, e.g. deactivating the pixelP1 and activating the pixel P2 shown in FIG. 4, or vice versa. In thisembodiment, when a plurality of signal source parameters AP areincluded, the first processor 115 adjusts a part of the signal sourceparameters AP each time or adjusts all of the signal source parametersAP at the same time. For example, the storage unit 117 previously storesa lookup table, and the first processor 115 compares the confident levelCL with the lookup table to update the at least one signal sourceparameter AP. After the at least one signal source parameter AP isupdated, the first processor 115 adjusts the signal source according tothe updated signal source parameter AP.

Step S65: The first processor 115 generates an intensity variationsignal (or PPG signal), as shown in FIG. 3, according to a plurality ofimage signals IF to be stored in the storage unit 117, and the intensityvariation signal (or PPG signal) is outputted through the transmissioninterface 119 thereof. In addition, other related information, such asthe image signal IF, the confident level CL and the signal sourceparameter AP, is also stored in the storage unit 117 to be used later.

Next, the physiological detection module 11 generates a next imagesignal according to the updated signal source parameter AP.

Referring to FIG. 7, it is a flow chart of an operating method of aphysiological detection system according to a second embodiment of thepresent disclosure, which includes the steps of: capturing an image(Step S71); calculating a confident level (Step S72); comparing theconfident level with at least one threshold (Step S73); updating atleast one signal source parameter and adjusting signal source (StepS74); storing information (Step S75); identifying whether to output thestored data (Step S76); and sending data (Step S77). The operatingmethod of this embodiment is applicable to the physiological detectionsystem 100 of FIG. 1.

The Steps S71-S75 of the second embodiment are similar to the StepsS61-S65 of the first embodiment and thus details thereof are notrepeated herein. In the second embodiment, after the information isstored in Step S75, in Step S76 the transmission interface 119 of thephysiological detection module 11 confirms whether a data sendingsignal, e.g. a polling signal or an interruption signal, is receivedfrom the application module 13. If the receiving of the data sendingsignal is confirmed, the transmission interface 119 sends the imagesignal IF, PPG signal, confident level CL (obtained in Step S72) andsignal source parameter AP (stored in the storage unit 117) to theapplication module 13 (Step S77). If the data sending signal is notreceived, the data is not sent by the transmission interface 119.Finally, the physiological detection module 11 generates a next imagesignal with the updated signal source parameter AP (updated in StepS74).

In the second embodiment, after receiving the intensity variation signal(or PPG signal), the application module 13 calculates physiologicalcharacteristics according to the intensity variation signal and performscorresponding controls.

Referring to FIG. 8, it is a flow chart of an operating method of aphysiological detection system according to a third embodiment of thepresent disclosure, which includes the steps of: capturing an image(Step S81); calculating a first confident level (Step S82); comparingthe first confident level with at least one threshold (Step S83);updating at least one signal source parameter (Step S84); storinginformation (Step S85); identifying whether to output the stored data(Step S86); sending data (Step S87); receiving updated signal sourceparameter (Step S88); and adjusting signal source (Step S89). Theoperating method of this embodiment is applicable to the physiologicaldetection system 100 of FIG. 1. In this embodiment, the Steps S81-S83and Step 85 are similar to the Steps S61-S63 and Step 65 of the abovefirst embodiment, and thus details thereof are not repeated herein.

The difference between the third embodiment and the second embodiment isthat, in the third embodiment, the application module 13 furthercalculates a second confident level CL2 according to the receivedintensity variation signal (or PPG signal) so as to further update thesignal source parameter AP if necessary. Accordingly, in Step S84 of thethird embodiment, the physiological detection module 11 only updates theat least one signal source parameter AP according to a comparison resultof comparing a first confident level CL and at least one threshold, butthe signal source is not yet adjusted. In this embodiment, the firstconfident level CL includes, for example, at least one of an averagebrightness value and uniformity.

Steps S86-S87: When the physiological detection module 11 confirms thata data sending signal (e.g. a polling signal or interruption signal) isreceived from the application module 13, the physiological detectionmodule 11 outputs an intensity variation signal (or PPG signal), whichis generated according to a plurality of image signals IF, to theapplication module 13. If the data sending signal is not received, StepS89 is directly entered such that the physiological detection module 11adjusts the corresponded sampling setting according to the currentsignal source parameter AP (e.g. updated in Step S84), e.g. adjusting atleast one of the exposure time, gain value, window of interest, focuslength and light receiving phase.

After receiving the intensity variation signal (or PPG signal), theapplication module 13 calculates a second confident level CL2 accordingto the intensity variation signal (or PPG signal), wherein the secondconfident level CL2 includes, for example, at least one of a PPG signalamplitude and a signal to noise ratio, which are described above andthus details thereof are not repeated herein. The application module 13further updates the at least one signal source parameter AP according tothe second confident level CL2 when necessary, e.g. when the PPG signalamplitude is not within a predetermined range or the SNR does not exceeda predetermined threshold, and sends back the updated signal sourceparameter AR In addition, the application module 13 further calculatesphysiological characteristics according to the intensity variationsignal (or PPG signal) and presents the physiological characteristics,e.g. a blood oxygenation, heart rate, respiration rate, SDPPG or thelike.

Step S88-S89: After receiving the updated signal source parameter APfrom the application module 13, the physiological detection module 11adjusts the corresponded sampling setting according to the updatedsignal source parameter AP.

Next, the physiological detection module 11 generates a next imagesignal according to the updated signal source parameter AP. In someembodiments, the signal source parameter AP is further configured toadjust a light emitting intensity of the light source module 111 of thephysiological detection module 11.

It should be mentioned that although FIG. 1 shows that the light sourcemodule 111 and the photo sensor 113 are disposed at the same side of theskin region SR to form the reflective detection device, the presentdisclosure is not limited thereto. In other embodiments, the lightsource module 111 and the photo sensor 113 are disposed at oppositesides of a skin region to form a transmissive detection device.

It is appreciated that in the above embodiments when the first confidentlevel and/or the second confident level satisfy the predeterminedrequirement, it means that the image signal IF captured by the photosensor 113 is suitable to calculate physiological characteristics andthus the at least one signal source parameter AP is not adjusted.

As mentioned above, when the optical physiological detection system isapplied to portable devices or wearable devices, the detection accuracyis decreased due to the uncertainty of the usage conditions. Therefore,the present disclosure further provides a physiological detection system(FIG. 1) and an operating method thereof (FIGS. 6-8) that adjust atleast one signal source parameter according to the confident level ofimage signals so as to improve the detection accuracy.

Although the disclosure has been explained in relation to its preferredembodiment, it is not used to limit the disclosure. It is to beunderstood that many other possible modifications and variations can bemade by those skilled in the art without departing from the spirit andscope of the disclosure as hereinafter claimed.

What is claimed is:
 1. A physiological detection system, comprising: aphysiological detection module comprising: a light source configured toprovide light to illuminate a skin region; a photo sensor comprising afirst pixel and a second pixel, and configured to detect emergent lightpassing the skin region with at least one signal source parameter andoutput an image signal, wherein the photo sensor further comprisesopaque metal layers around the first pixel and the second pixel torespectively form an overhead first light tunnel toward the first pixeland a stepped second light tunnel toward the second pixel to cause thefirst pixel and the second pixel to receive the emergent light from theskin region at different first and second light receiving anglesrespectively, and the different first and second light receiving anglesdefine the at least one signal source parameter, and a first processorconfigured to calculate a first confident level according to the imagesignal and update the at least one signal source parameter according tothe first confident level.
 2. The physiological detection system asclaimed in claim 1, wherein the first confident level comprises at leastone of an average brightness value and uniformity.
 3. The physiologicaldetection system as claimed in claim 1, wherein the at least one signalsource parameter further comprises at least one of an exposure time, again value, a window of interest, and a focus length, and the window ofinterest is a pixel area of the photo sensor having a higher confidentlevel than other pixels or having brightness within a predeterminedrange.
 4. The physiological detection system as claimed in claim 1,wherein an emission wavelength of the light source is between 300 nm and940 nm.
 5. The physiological detection system as claimed in claim 1,wherein the at least one signal source parameter is further configuredto control a light emitting intensity of the light source.
 6. Thephysiological detection system as claimed in claim 1, wherein thephysiological detection module further comprises a transmissioninterface coupled to the first processor, the first processor is furtherconfigured to generate an intensity variation signal according to aplurality of image signals, and the transmission interface is configuredto output the intensity variation signal.
 7. The physiological detectionsystem as claimed in claim 6, wherein the physiological detection systemfurther comprises an application module coupled to the physiologicaldetection module, and the application module comprises a secondprocessor configured to calculate physiological characteristicsaccording to the intensity variation signal.
 8. The physiologicaldetection system as claimed in claim 6, wherein the physiologicaldetection system further comprises an application module coupled to thephysiological detection module, and the application module comprises asecond processor configured to calculate a second confident levelaccording to the intensity variation signal and update the at least onesignal source parameter according to the second confident level.
 9. Thephysiological detection system as claimed in claim 8, wherein the secondconfident level comprises at least one of a PPG signal amplitude and asignal to noise ratio.
 10. The physiological detection system as claimedin claim 7, wherein the application module is selected from a groupconsisting of a portable electronic device, a wearable electronicdevice, a home appliance, a vehicle device and a medical device.
 11. Anoperating method of a physiological detection system, the physiologicaldetection system comprising a physiological detection module whichcomprises a photo sensor having a first pixel and a second pixel, theoperating method comprising: detecting, by the physiological detectionmodule, emergent light from a skin region with at least one signalsource parameter to generate an image signal, wherein the photo sensorfurther comprises opaque metal layers around the first pixel and thesecond pixel to respectively form an overhead first light tunnel towardthe first pixel and a stepped second light tunnel toward the secondpixel to cause the first pixel and the second pixel to receive theemergent light from the skin region at different first and second lightreceiving angles respectively, and the different first and second lightreceiving angles define the at least one signal source parameter;calculating, by the physiological detection module, a confident levelaccording to the image signal; comparing, by the physiological detectionmodule, the confident level with at least one threshold; and updating,by the physiological detection module, the at least one signal sourceparameter according to a comparison result of comparing the confidentlevel and the at least one threshold.
 12. The operating method asclaimed in claim 11, wherein the confident level comprises at least oneof an average brightness value and uniformity.
 13. The operating methodas claimed in claim 11, wherein the at least one signal source parameterfurther comprises at least one of an exposure time, a gain value, awindow of interest, and a focus length, and the window of interest is apixel area of the physiological detection module having a higherconfident level than other pixels or having brightness within apredetermined range.
 14. The operating method as claimed in claim 11,further comprising: generating, by the physiological detection module,an intensity variation signal according to a plurality of image signals;and outputting, by the physiological detection module, the intensityvariation signal.
 15. The operating method as claimed in claim 14,wherein the physiological detection system further comprises anapplication module coupled to the physiological detection module, andthe operating method further comprises: receiving the intensityvariation signal with the application module; and calculating, by theapplication module, physiological characteristics according to theintensity variation signal.
 16. An operating method of a physiologicaldetection system, the physiological detection system comprising aphysiological detection module, which comprises a photo sensor having afirst pixel and a second pixel, and an application module coupled toeach other, the operating method comprising: detecting, by thephysiological detection module, emergent light from a skin region withat least one signal source parameter to generate an image signal,wherein the photo sensor further comprises opaque metal layers aroundthe first pixel and the second pixel to respectively form an overheadfirst light tunnel toward the first pixel and a stepped second lighttunnel toward the second pixel to cause the first pixel and the secondpixel to receive the emergent light from the skin region at differentfirst and second light receiving angles respectively, and the differentfirst and second light receiving angles define the at least one signalsource parameter; calculating, by the physiological detection module, afirst confident level according to the image signal; outputting, by thephysiological detection module, an intensity variation signal accordingto a plurality of image signals; calculating, by the application module,a second confident level according to the intensity variation signal;and updating the at least one signal source parameter according to thefirst confident level and the second confident level.
 17. The operatingmethod as claimed in claim 16, wherein the first confident levelcomprises at least one of an average brightness value and uniformity,and the second confident level comprises at least one of a PPG signalamplitude and a signal to noise ratio.
 18. The operating method asclaimed in claim 16, wherein the at least one signal source parameterfurther comprises at least one of an exposure time, a gain value, awindow of interest, and a focus length, and the window of interest is apixel area of the physiological detection module having a higherconfident level than other pixels or having brightness within apredetermined range.
 19. The operating method as claimed in claim 16,further comprising: calculating, by the application module,physiological characteristics according to the intensity variationsignal.
 20. The operating method as claimed in claim 16, furthercomprising: adjusting a light emitting intensity of a light source ofthe physiological detection module according to the at least one signalsource parameter.